Introduction/Background Intravenous leiomyomatosis (IVL) is a rare disease characterized by intraluminal extension of benign smooth muscle tissue from the uterus into veins. This can cause congestive heart failure, syncope, and even sudden death if the tricuspid valve is obstructed by a tumor thrombus.

Methodology A 46-year-old woman (G6:2–4-2) was admitted to the Gynecologic Oncology Department complaining of pain in her left thigh and swelling of her left leg. Previously (2012–2013) the patient was treated for non-Hodgkin’s lymphoma stage IV; progression of lymphoma or other malignant neoplasia was suspected. Performed CT angiography (CTA) of the pelvis, abdomen and chest, as well as transthoracic echocardiography. A solid tumor was found in the pelvis and a tumor thrombus in the left iliac veins, inferior vena cava with a transition to the right atrium.

Results In connection with the volumetric formations visualized on CTA in the pelvis and veins, a diagnostic laparotomy was performed. Laparotomy revealed uterine masses, a tumor biopsy and bilateral salpingo-oophorectomy were performed, and the diagnosis of IVL was morphologically confirmed. After an interdisciplinary consultation, the patient underwent a radical operation using cardiopulmonary bypass: hysterectomy with removal of a tumor thrombus from the pelvic veins, inferior vena cava and heart. Within 6 months there was no recurrence.

Conclusion Intravenous leiomyomatosis is an extremely rare disease affecting predominantly premenopausal women. It should be suspected in women with uterine leiomyoma presenting with signs of heart failure and tumor thrombus. An effective method of treatment for IVL is the complete surgical removal of the tumor.